JPS6019061B2 - tape guide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tape guide in a magnetic line drawing reproduction machine (VTR), etc., and is intended to guide and run a tape-like body smoothly.

Below, we will explain a tape guide used in a diagonal scanning rotary head type VTR that records and reproduces signals, especially video signals, on a magnetic tape.In the conventional simple type VTR, a cylindrical tape guide as shown in Fig. 1 is used. Of the upper and lower cylinders 1 and 2 that make up the cylinder, a guide portion 2' is provided on the outer peripheral surface of the fixed cylinder 2, and the magnetic tape 3 is attached to the guide post 4.
, 4, the tape is wound diagonally and runs along the guide portion 2' of the tape guide. and,. At this time, a magnetic head 6. The wound magnetic tape 3 has been rearranged so that it slightly protrudes near the slit 5.
Recording and reproducing are performed by contacting with. Incidentally, the magnetic tape 3 and the rotating cylinder 1 each run and rotate in the direction of the solid line arrow. The reason why the magnetic tape 3 is wound in this way is that an air film is formed between the magnetic tape 3 and the magnetic tape 3 as the rotary cylinder 1 rotates at high speed, which reduces the frictional force between the magnetic tape 3 and the tape guide. The tape tension at the entrance and exit T. This is to reduce the difference in T2 and make running smoother, thereby reducing the running load.
Great effects such as reduction of jitter can be obtained. On the other hand, the amount of air film formed varies depending on the tape width of the magnetic tape 3 being wound as shown in Fig. 2, and the amount of air film formed varies depending on the tape width of the magnetic tape 3 being wound. Formation is difficult to obtain, and the higher the tape tension value, the more the running load increases.
As the magnetic tape 3 and the rotating cylinder 1 repeatedly come into contact and separate from each other, problems such as wow and flutter and jitter increase occur. In view of this, the present invention aims to provide a tape guide that can obtain a sufficient air film effect even with a tape having a relatively narrow tape width. A groove is provided that extends from the inner circumference to the outer circumference at an angle with respect to the rotating direction of the rotating cylinder, and air flowing into this groove when the rotating cylinder rotates increases the pressure in the slit covered with the magnetic tape. is floated above the tape guide, promoting the formation of an air film as the rotating cylinder rotates at high speed, and achieving a sufficient air film effect.
Next, to explain the details of the present invention, in FIGS. 3 and 4, a rotating shaft 8 passing through the fixed cylinder 2 side is rotatably supported by a bearing 9, and the rotating shaft 8
A disk 10 is fixed so as to rotate in a plane perpendicular to the axis of rotation, and a rotating cylinder 1 mounted on the disk 10 is integrally coupled with bolts 11, and a driving source 7 rotates the rotating shaft 8. By doing so, they rotate together in the direction of the arrow.

In addition, as shown in FIG. 3b, the rotary cylinder 1 has an inner peripheral portion that is inclined with respect to the rotational direction of the rotary cylinder 1, as shown in FIG. A plurality of concave grooves 12 extending toward the outer periphery are carved in a predetermined curve, and the outer periphery end of both ends of these grooves 12 is open, and the inner periphery end is slit to prevent the inflowing air from flowing out. It is closed to increase the air pressure inside 5.
Further, as shown in FIG.
3, air should flow in as the rotary cylinder 1 rotates in the direction of the arrow.It has a curve in the opposite direction to the groove 12 of the rotary cylinder 1 and is carved on the surface B-B side forming the slit 5. . Due to the presence of these grooves 12 and 13, the rotating sill 1
When rotates at high speed, air flows into the slit 5 12,
13, the air pressure in the slit 5 increases,
Air pressure is applied to the magnetic tape 3 wound around the tape guide, which is separated from the outer peripheral surface of the tape guide, thereby promoting the effect of the air film formed between the rotary cylinder 1 and the magnetic tape 3. Even with a tape having a relatively narrow tape width, sufficiently smooth tape running can be obtained. FIG. 5a shows an embodiment configuration that makes the present invention more effective, in which air flows out from the grooves 12 and 13,
Air stopper 1 is installed to prevent air pressure from decreasing.
4, the slit 5 is substantially closed from the inside of the tape guide.

FIG. 5b is a perspective view of the air stopper 14, whose lower part is fixed to the inner surface of the fixed cylinder 2, and whose upper part is fixed to the inner surface of the fixed cylinder 2. It is placed either in close contact with the inner surface of the tube or with an extremely narrow gap between the two. 6th
In the figure, a new convex portion 15 is provided on the surface A-A forming the slit 5 of the rotary cylinder to obtain the effect of an air stopper.

As shown in FIG. 7, the groove 16 can be sufficiently effective even if both ends are closed, and even if the groove is not provided in the fixed cylinder 2 but only in the rotary cylinder 1, or if the slit width is If the cylinder is configured to be extremely small, the groove may be provided only in the fixed cylinder 2.

Even if the direction in which the grooves formed on the opposing surfaces of the slits are used is set in such a direction that the air moving as the rotating cylinder 1 rotates is actively guided toward the outer periphery, the intended purpose will still be achieved. be. Furthermore, the present invention is not limited to magnetic tapes, but is extremely useful in smoothing the running of general tape-shaped bodies. According to the present invention as explained above,
Since a groove is provided on the opposing surface of the fixed cylinder and the rotating cylinder that extends from the inner circumference to the outer circumferential portion at an angle with respect to the rotating direction of the rotating cylinder, as the rotating cylinder rotates, the opposing surface of the fixed cylinder and the rotating cylinder Air is discharged from the slit formed by the tape, and an air film is formed well over the entire length of the opposing portion of the tape and tape guide.
Therefore, even when the tape width is narrow or the tape tension is high, a sufficient air film formation effect can be obtained, and there is no disturbance applied to the tape unlike when grooves are formed on the outer circumferential surface of a rotating cylinder, thus reducing jitter. It is possible to realize smooth and stable tape running while solving the problem of occurrence. Furthermore, even when running under high tension, there is no risk of contact with the tape near the edge of the upper rotating cylinder forming the slit.

[Brief explanation of the drawing]

Fig. 1 is an operation explanatory diagram showing an example of the use of a tape guide in a conventional diagonal scanning rotary head type magnetic recording/reproducing device, Fig. 2 is a correlation diagram between tape width and air film amount, Fig. 3 a, b
4 is a configuration diagram of a rotating cylinder in an embodiment of the present invention, FIGS. 4a and 4b are configuration diagrams of a fixed cylinder, and FIGS.
b is a configuration diagram of a tape guide showing the second embodiment;
The figure is a configuration diagram of a tape guide showing a third embodiment, and FIG. 7 is a configuration diagram showing a fourth embodiment. 1... Rotating cylinder, 2... Fixed cylinder, 2'...
-Guide section, 5...slit, 6...magnetic head, 7...drive source, 8...rotating shaft, 9...bearing, 10...disk, 11... Bolt, 12, 13,
16...Groove, 14...Air stopper, 15...Protrusion. Heron Mother Heron 2 Prisoner J Prisoner Mother 4 Koushu 5 Illustration Crane〆Mother Eagle 7 Kyou

Claims (1)

[Claims] 1. A fixed cylinder and a rotating cylinder arranged on the same axis as the fixed cylinder and rotated by a drive source so as to form a slit of a predetermined width between the fixed cylinder and the slit. A tape guide having a groove formed on a facing surface thereof, the groove being inclined with respect to the rotational direction of the rotary cylinder, extending from the inner circumferential portion to the outer circumferential portion, and having an end portion of the inner circumferential portion closed.